Home › Pies of All Kinds › Boiled Icing
Boiled Icing
1 cup granulated sugar 3 tablespoons cold water 1 egg (white) 1 teaspoon flavoring to taste Put sugar and water in pan, stir and put on stove. When dissolved, let boil till it hairs, but do not stir. Beat the white of egg to a stiff froth, and add boiled sugar, beating all the while. When it begins to stiffen, add flavoring and beat. When quite thick and before it is cold, it is ready for use. Half a teaspoon of cream of tartar may be added. Sometimes, also, milk is used instead of water.
A standard boiled or "seven-minute" style icing: hot sugar syrup beaten into whipped egg white until it sets to a glossy meringue. The whole thing turns on the syrup temperature and on not stirring it.
- "Till it hairs"This is the thread stage, roughly 230-235F on a candy thermometer, when a drop pulled between finger and spoon draws a fine hair. Higher, toward 240F, gives a firmer icing that sets almost immediately; lower gives a syrup that never stiffens.
- Why you must not stirOnce the sugar has dissolved, stirring drags crystals up the pan wall and back into the syrup, and the finished icing turns grainy. Wash the sides down with a wet pastry brush instead, or cover the pan for the first minute so steam does it.
- Cream of tartarThe optional half teaspoon is an acid. Added to the syrup at the start it inverts some of the sucrose so the syrup resists crystallizing; beaten into the white instead, it helps stabilize the froth. The recipe does not say which, and either use is defensible.
- BeatingWritten for a hand whisk and a second pair of hands. With a stand mixer, whip the white to stiff peaks, then pour the hot syrup in a thin steady stream down the side of the bowl with the machine running, avoiding the whisk itself. Keep beating until the bowl is barely warm.
- Egg whiteThe hot syrup cooks the white only partially, and this icing is not held at a safe temperature for any length of time. Pasteurized whites are the sensible choice if serving anyone elderly, pregnant, very young or immune-compromised.
- FlavoringA teaspoon of vanilla is the default; almond, lemon or rose extract were all common. Add it at the end, off the heat, since alcohol-based extracts flash off in hot syrup.
- The milk variationMilk in place of water gives a softer, faintly caramel icing, but the milk solids scorch easily. Use a heavy pan and low heat, and expect an off-white result rather than a pure white one.
- Yield and timingOne cup of sugar and a single white make a modest amount, enough for the top of a small cake or a thin coat on one layer. Spread it while still warm and workable; it crusts within minutes and cracks if pushed around after that.
Boiled icing was the home cook's answer to a problem that fondant and buttercream solved differently: how to get a white, firm, non-greasy finish on a cake without a confectioner's equipment. It depends on cheap, reliably fine granulated sugar, which became a North American kitchen staple over the later nineteenth century; before that, loaf sugar had to be broken and pounded first. The Five Roses Cook Book was published by the Lake of the Woods Milling Company as advertising for its flour, and its recipes were contributed by Canadian housewives who used that flour, which helps explain the telegraphic style. "Till it hairs" is the pre-thermometer vocabulary of sugar boiling, one stage in a ladder that ran from thread through soft ball, hard ball and crack to caramel, all of them judged by hand and eye.